<!doctype html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
    <meta name="description" content="">
    <meta name="author" content="Mark Otto, Jacob Thornton, and Bootstrap contributors">
    <meta name="generator" content="Jekyll v4.1.1">
    <title>Signin Template · Bootstrap</title>

    <link rel="canonical" href="https://getbootstrap.com/docs/4.5/examples/sign-in/">

    <!-- Bootstrap core CSS -->
    <link href="../../assets/dist/css/bootstrap.min.css" rel="stylesheet">

    <style>
        .bd-placeholder-img {
            font-size: 1.125rem;
            text-anchor: middle;
            -webkit-user-select: none;
            -moz-user-select: none;
            -ms-user-select: none;
            user-select: none;
        }

        @media (min-width: 768px) {
            .bd-placeholder-img-lg {
                font-size: 3.5rem;
            }
        }
    </style>
    <!-- Custom styles for this template -->
    <link href="../../assets/dist/css/signin.css" rel="stylesheet">
    <script>
        // 判断是登录账号和密码是否为空
        function check() {
            var usercode = document.forms[0]["usercode"].value;
            var password = document.forms[0]["password"].value;

            if (usercode === "" || password === "") {
                alert("账号或密码不能为空！");
                return false;
            }
            return true;
        }
    </script>


</head>
<body class="text-center">
<form class="form-signin" action="/login,action" onsubmit="return check()">
    <img class="mb-4" src="../../assets/brand/collegeicon2.jpg" alt="">
    <h1 class="h3 mb-3 font-weight-normal">课程管理系统</h1>
    <label for="usercode" class="sr-only">Account</label>
    <input type="text" id="usercode" class="form-control" placeholder="账号" autofocus>
    <label for="password" class="sr-only">Password</label>
    <input type="password" id="password" class="form-control" placeholder="密码">
    <div class="checkbox mb-3">
        <label>
            <input type="checkbox" value="remember-me"> Remember me
        </label>
    </div>
    <button class="btn btn-lg btn-primary btn-block" type="submit" >Sign in</button>
    <p class="mt-5 mb-3 text-muted">&copy; 2017-2020</p>
</form>
</body>
</html>
`